Method of Industrial Producing Elastomeric Yarn and Fabric thereof

ABSTRACT

The present invention relates to make stretch yarn by using at least two roving and two elastomeric filaments with variable draft to allow the yarn made in the fabric to get good stretch, good recovery and good shrinkage. The invention is applicable for all types of fibers material and is not limited in the yarn count. The said invention yarn is woven into fabrics exhibiting the excellent stretch characteristics and functional performance for commercial application.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to Hong Kong Short-Term PatentApplication No. 19131094.5 filed on Oct. 16, 2019, the disclosure ofwhich is incorporated by reference herein in its entirety.

BACKGROUND Field of the Invention

The present invention relates to elastomeric yarns and fabrics, and amethod of producing the same.

Terminology

For the technical terms elaborated as follows and used herein, referenceis made to Textile Terms and Definitions (Ninth Edition) and ASTM.

-   -   Elastomer: any polymer having high extensibility together with        rapid and substantially complete elastic recovery.    -   Elastomeric Filament: a filament formed from elastomer, for        example elastane or elastodiene.    -   Filament: a fiber of indefinite length.    -   Roving: a name given, individually or collectively, to the        relatively fine fibrous strands used in the later of final        processes of preparation of spinning.    -   Stretch: yarn capable of a pronounced degree of stretch and        recovery from stretch.    -   Draft: to reduce the linear density of a fibrous assembly by        drawing.    -   Shrinkage: reduction in length (or width) of a fiber, yarn,        fabric or other textile, induced by conditioning, wetting,        steaming, chemical treatment, wet processing as in laundering,        dry heat or mechanical action.    -   Fabric Growth: is calculated from the length difference between        the bench marks prior to application of the tension and after        relaxation.    -   Twist Multiplier: means in a yarn, the product of twist level        and is the same as Twist per inch divided by square root of Ne.

DESCRIPTION OF RELATED ART

Conventional yarn is a product of substantial length and relativelysmall cross-section consisting of fibers and/or filament(s) with orwithout twist. The choice of fibers and the specification on the yarndetermines the qualities and the characteristics of the fabric.Nowadays, more and more consumers are concentrating to find someproducts with functional properties like thermal resistance, easy-care,easy dry, UV protection, etc. The last but not the least is body-fitproducts which have good stretch and recovery.

Throughout the years, spinners tried to produce the yarn with highstretch by different material, different denier of the spandex andcombination in order to get those characteristics so a wide range ofproducts have been developed. Of course, they have a lot of restrictionamongst these and need additional finishing process which is not costeffective.

As years before, many spinners commonly use that pre-stretchedelastomeric fibers (that called spandex or elastane) and guided in thecenter of the drafted fiber sheath to produce those core stretch yarn.By controlling the denier and the draft, different stretch result willcome out. Woven fabric made of such yarn will have the problem of poorrecovery/shrinkage, the higher the stretch, the poorer the result. Insome cases, additional heat-setting is a necessary to improve thedimensional stability of the fabric which is cost consuming.

U.S. Pat. Nos. 3,671,379, 6,782,923 and 7,143,790 disclose the way ofmaking woven stretch fabric by comprising those bare polyester filamentssaid bi-component polyester filament. The invention is limited on thestretch, in general, in the range from 15-25% but not limited and havesynthetic feel although the recovery is acceptable. Only limited use inweft of the denim without over dyed and cannot use in piece dyed unlessdo the two parts dyed. In this case, the cost is higher and the stretchproperties are also affected.

U.S. Pat. Nos. 7,299,828 and 7,637,091 disclose that core spun yarn withbi-component polyester comprising poly(ethylene terephthalate) andpoly(trimethylene terephthalate) or poly(trimethylene terephthalate) andpoly(tetramethylene terephthalate) or poly(trimethylene terephthalate)and poly(trimethylene terephthalate) can improve the synthetic feel witha natural fiber look. However, its stretch is affected and much worsethan bare bi-component polyester.

Others like U.S. Pat. Nos. 8,093,160 and 9,303,336 disclose that corespun yarn with polyester filament (with/without elastic) and elastomericfibers (spandex) which can improve the stretch to the range 20%-60% andcan achieve a good recovery. However, it faces the problem of the whiteportion at the piecing part and some un-coverage of those filaments andis limited to certain extent for using in warp of denim and piece dyedstretch fabric.

SUMMARY OF THE INVENTION

The objective of the present invention is to make ring spun yarn byusing different drafts on the core elastomeric filaments in the ringspun yarn and by which, not limited, to improve the mechanical to getthe good shrinkage, good recovery and stretch.

The present invention is a ring spun yarn with at least two elastomericfilament with at least two different main drafts. The main draft inindividual filament is the average of variable draft used. In oneembodiment, said filament ranges from 20 deniers to 500 deniers.Preferably, said filament ranges from 20 deniers to 140 deniers.

The present invention comprises two fibrous sheath and said, are thoseshort staple fibers can be natural or synthetic fibers like cotton,rayon, polyester, wool, acrylic and a combination thereof. And have norestriction same as the normal ring spun yarn.

In another embodiment said, the yarn count of present invention has nolimitation, preferably ranging from English Cotton yarn count from aboutNe 4 to Ne 60.

The present invention also has an objective to use this composite yarnis in denim and piece dyed fabric and not limited to knit fabric as wellas sweater.

Other aspects of the present invention are disclosed as illustrated bythe embodiments hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the side view of the apparatus for the present inventionof normal ring spinning machine.

FIG. 2 depicts the side view of the apparatus for the present inventionof using two elastomeric filaments with different drafts with tworoving.

FIG. 3 depicts the view of position of the elastomeric filaments in theyarn with variable draft in the same yarn.

FIG. 4 depicts the view of position of the elastomeric filament in theyarn if the draft is the same.

FIG. 5 depicts the side view of the apparatus for the present inventionof using three elastomeric filaments with different drafts with threeroving.

FIG. 6 depicts the view of position of three elastomeric filaments inthe yarn with variable draft.

DETAILED DESCRIPTION

The objective of the present invention is to find a way to produce aring spun yarn by using elastomeric filament (not limited to spandex andother elastomers also applicable) to achieve good elongation, goodrecovery and less shrinkage without affecting other physical propertiesboth in yarn and in fabric. The present yarn is suitable for denim,piece dyed, circular knit and sweater as well. The present invention isa ring spun yarn comprising at least two elastomeric filaments (notlimited to spandex and other elastomers also applicable) with at leasttwo different mean drafts. And said the filament ranges from 20 deniersto 500 deniers, and preferably from 20 deniers to 140 deniers, whereinthe draft of the filaments ranges from 1.05 to 5. In another embodiment,the yarn count of the ring spun yarn has no limitation and said rangesfrom Ne 4 to 60 preferable.

It is well known that the ways of making staple spun yarns are ringspinning, Open-End Spinning and that of Jet Spinning, amongst those,Ring Spinning is one of the most common way. The present invention isusing this Ring Spinning Technology.

The embodiments and the examples disclosed herein are made to show thepresent invention and are not intended to be limiting.

In the ring spinning production, spinning is the final stage ofprocessing that produces a continuous twisted strand of fibers which hasreceived its final attenuation. In FIG. 1, it shows the skills in theart.

During the normal spinning process, the main sections include material[A], drafting [B] and twisting [C] as in FIG. 1. In the presentinvention, the material used in [A] is those natural or syntheticsstaple fibers, not limited to cotton, rayon, polyester, wool, acrylic,etc. or a combination thereof. It consists of two roving with the samematerial or two different materials.

In the drafting system [B] consists of three pair of rolls 41, 42, 43and for most system, aprons are mounted with the middle rolls 42. Thespeed ratio of each pair of roll is so adjusted that the fibers 10 aredelivered through a trumpet 61 from a slowly moving pair of rolls 43towards a rapidly moving pair of rolls 41. The final yarn count dependson the yarn count of the material 10 and the ratio of the linear speedbetween these pair of rolls 41, 43 for those normal yarns. The strengthof the yarn depends on the material and the twist added in the twistingsection [C].

The present invention of this stretch yarn is produced by inserting atleast two elastomeric filaments into the core of the fibers sheath ofthe described ring spun yarn. The apparatus [D] is shown in FIG. 2. Thematerial of these two types of elastomeric filaments 21, 31 can be thesame or with different material, like those spandex or elastomer or acombination thereof. The draft is one of the most important relatedfactors in the present invention. During the spinning process, theelastomeric filaments 21 are unwound from the rollers 22, 23 whereaselastomeric filaments 31 are unwound from the rollers 32, 33. The drafton the elastomeric filament 21 is controlled by the ratio of the surfacespeed of front roller 41 and roller 23 whereas the draft on theelastomeric filament 31 is controlled by the ratio of the surface speedof front roller 41 and the roller 33. In one embodiment of the presentinvention, the mean drafts of these filaments are ranging from 1.05 to5. And that the elastomeric filament is positioned in the left to centerof the fibrous sheath but not limited.

In the present invention, the ratio of the surface speed of the frontroller 41 and roller 23, and the surface speed of roller 41 and roller33 are controlled by program throughout the spinning process. Thevariables are denoted as:

Surface speed of roller 41/surface speed of roller 23: D₂₃₁, D₂₃₂, D₂₃₃. . . D_(23X)Surface speed of roller 41/surface speed of roller 33: D₃₃₁, D₃₃₂, D₃₃₃. . . D_(33X)

The draft of D₂₃₁, D₂₃₂, D₂₃₃ D_(23X) is running at different time as in

T₂₃₁, T₂₃₂, T₂₃₃ . . . T_(23X)

The draft of D₃₃₁, D₃₃₂, D_(333 . . .) & D_(33X) is running at differenttime as in

T₃₃₁, T₃₃₂, T₃₃₃ . . . T_(33X)

Therefore, the mean draft [D₂₁] of that filament 21 is calculated as

$D_{21} = \frac{{D_{231} \times T_{231}} + {D_{232} \times T_{232}} + {D_{233} \times T_{233}\mspace{11mu}\ldots} + {D_{23X} \times T_{23X}}}{T_{231} + T_{232} + {T_{233}\mspace{11mu}\ldots} + T_{23X}}$

The mean draft [D₃₁] of that filament 31 is calculated as

$D_{31} = \frac{{D_{331} \times T_{331}} + {D_{332} \times T_{332}} + {D_{333} \times T_{333}\mspace{11mu}\ldots} + {D_{33X} \times T_{33X}}}{T_{331} + T_{332} + {T_{333}\mspace{11mu}\ldots} + T_{33X}}$

In practical, the difference of those variable drafts is ±50% amongstindividual mean draft, but not limited.

It is calculated as:

0.50≤(D ₂₃₁−1)/(D ₂₁−1)≤1.50

0.50≤(D ₂₃₂−1)/(D ₂₁−1)≤1.50

0.50≤(D _(23X)−1)/(D ₂₁−1)≤1.50 . . . etc.

D ₂₁ ,D ₂₃₁ ,D ₂₃₂ . . . D _(23X)≥1 and

0.50≤(D ₃₃₁−1)/(D ₃₁−1)≤1.50

0.50≤(D ₃₃₂−1)/(D ₃₁−1)≤1.50

0.50≤(D ₃₃₃−1)/(D ₃₁−1)≤1.50 . . . etc.

D ₃₁ ,D ₃₃₁ ,D ₃₃₂ . . . D _(33X)≥1

In FIG. 3, it is the view of the position of that elastomeric filamenton the yarn with different draft ratio and time whereas, in FIG. 4, thedraft ratio on single elastomeric filament is the same and not limitedthat both draft of the elastomeric filament is the same.

Another embodiment of the invention, have inserted 3 elastomericfilaments into the core of the fibers sheath as in FIG. 5. The materialof these three types of elastomeric filaments 21, 31, 51 can be the sameor with different material but at least two of them are elastomericfilaments (spandex) and the other one can be those polyester, nylon, PEsynthetic filaments, not limited to elastic or inelastic or acombination thereof. During the spinning process, the filament 21 isunwound from the rollers 22, 23 whereas filament 31 is unwound from therollers 32, 33 and filament 51 is unwound from the rollers 52, 53. Thedraft on the filament 21 is controlled by the ratio of the surface speedof front rollers 41 and roller 23 whereas the draft on the filament 31is controlled by the ratio of the surface speed of front roller 41 andthe roller 33 and the same. The draft on the filament 51 is controlledby the surface speed of front roller 41 and roller 53. In one embodimentof the present invention, the mean drafts of these filaments are rangingfrom 1.05 to 5. And that the elastomeric filament is positioned in theleft to center of the fibrous sheath but not limited.

In the present invention, the ratio of the surface speed of the frontroller 41 and roller 23, the surface speed of roller 41 and roller 33,and the surface speed of roller 41 and roller 53 are controlled byprogram. The variables are denoted as:

Surface speed of roller 41/surface speed of roller 23: D₂₃₁, D₂₃₂, D₂₃₃. . . D_(23X)Surface speed of roller 41/surface speed of roller 33: D₃₃₁, D₃₃₂, D₃₃₃. . . D_(33X)Surface speed of roller 41/surface speed of roller 53: D₅₃₁, D₅₃₂, D₅₃₃. . . D_(53X)

The draft of D₂₃₁, D₂₃₂, D₂₃₃ . . . D_(23X) is running at different timeas in

T₂₃₁, T₂₃₂, T₂₃₃ . . . T_(23X)

The draft of D₃₃₁, D₃₃₂, D₃₃₃ . . . D_(33X) is running at different timeas in

T₃₃₁, T₃₃₂, T₃₃₃ . . . T_(33X)

The draft of D₅₃₁, D₅₃₂, D₅₃₃ . . . D_(53X) is running at different timeas in

T₅₃₁, T₅₃₂, T₅₃₃ . . . T_(53X)

Therefore, the mean draft [D₂₁] of that filament 21 is calculated as

$D_{21} = \frac{{D_{231} \times T_{231}} + {D_{232} \times T_{232}} + {D_{233} \times T_{233}\ldots} + {D_{23X} \times T_{23X}}}{T_{231} + T_{232} + {T_{233}\ldots} + T_{23X}}$

The mean draft [D₃₁] of that filament 31 is calculated as

$D_{31} = \frac{{D_{331} \times T_{331}} + {D_{332} \times T_{332}} + {D_{333} \times T_{333}\ldots} + {D_{33X} \times T_{33X}}}{T_{331} + T_{332} + {T_{333}\ldots} + T_{33X}}$

The mean draft [D₅₁] of that filament 51 is calculated as

$D_{51} = \frac{{D_{531} \times T_{531}} + {D_{532} \times T_{532}} + {D_{533} \times T_{533}\ldots} + {D_{53X} \times T_{53X}}}{T_{531} + T_{532} + {T_{533}\ldots} + T_{53X}}$

In practice, the difference of those variable drafts is ±50% amongstindividual mean draft, but not limited.

Same as previous, the variable draft should be as

0.50≤(D ₅₃₁−1)/(D ₅₁−1)≤1.50

0.50≤(D ₅₃₂−1)/(D ₅₁−1)≤1.50

0.50≤(D ₅₃−1)/(D ₅₁−1)≤1.50 . . . etc.

D ₅₁ ,D ₅₃₁ ,D ₅₃₂ . . . D _(53X)≥1

The following examples demonstrate the present invention and itscapability for use in manufacturing of different specification fabric.

Example 1: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 100% cotton Ne 10 inthe warp and with Ne16 Stretch yarn in accordance with the presentinvention. The invention in the weft yarn is with cotton fibrous sheathand core with two 40D denier. Both of the average draft is with 3.5. Wecan see the sample had weight 11.8 oz/sq.yd. (after washed), goodstretch (26.13%), good shrinkage (−7%) and growth (3.6%).

Example 2: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 100% cotton Ne 8 inthe warp and with Ne16 Stretch yarn in accordance with the presentinvention. The invention in the weft yarn is with cotton fibrous sheathand core with two 40D denier. Both of the average draft is with 3.8. Wecan see the sample had weight 11.9 oz/sq.yd. (after washed), goodstretch (36.26%), good shrinkage (−11%) and acceptable growth (4.9%).

Example 3: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 100% cotton Ne10 slubin the warp and with Ne16 Stretch yarn in accordance with the presentinvention. The invention in the weft yarn is with cotton fibrous sheathand core with two 40D denier with less pick, said 48. Both of theaverage draft is with 3.5. We can see the sample had weight 12 oz/sq.yd.(after washed) and resulted in high stretch (44.26%) and still have goodshrinkage (−9%) and acceptable growth (4.8%).

Example 4: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 100% cotton Ne10 slubin the warp and with 70% Polyester/30% Rayon Ne16 Stretch yarn inaccordance with the present Invention. The invention in the weft yarn iswith cotton fibrous sheath and core with two 40D denier. Both of theaverage draft is with 3.8. We can see the sample had weight 11.8oz/sq.yd. (after washed), good stretch (31.33%), good shrinkage (−8%)and growth (3.2%).

Example 5: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 100% cotton Ne14 slubin the warp and with 70% Polyester/30% Rayon Ne16 Stretch yarn inaccordance with the present Invention. The invention in the weft yarn iswith cotton fibrous sheath and core with two 40D denier. Both of theaverage draft is with 3.8. We can see the sample had weight 11.8oz/sq.yd. (after washed) and have a higher stretch (65.2%) at goodshrinkage (−13%) and acceptable growth (6.73%).

Example 6: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 50% cotton/50% RayonNe12 slub in the warp and with 70% Polyester/30% Rayon Ne16 Stretch yarnin accordance with the present Invention. The invention in the weft yarnis with cotton fibrous sheath and core with two 40D denier. Both of theaverage draft is with 3.8. We can see the sample had weight 12.2oz/sq.yd. (after washed), good stretch (34.4%), good shrinkage (−9%) andgrowth (3.06%).

Example 7: Denim Warp & Weft Stretch Fabric

A two ways denim stretch fabric, construction 3/1 RHT, with 100% cottonNe10 slub core 40D Spandex in the warp and with 70% Polyester/30% RayonNe16 Stretch yarn in accordance with the present Invention. Theinvention in the weft yarn is with cotton fibrous sheath and core withtwo 40D denier. Both of the average draft is with 3.8. We can see thesample had weight 13.5 oz/sq.yd. (after washed), good warp/weft stretch(14.13%/31.33%), good warp/weft shrinkage (−13%/−8%) and acceptablegrowth (2.93%/4.8%).

Example 8: Denim Weft Stretch Fabric

A denim stretch fabric, construction 3/1 RHT, with 91% cotton/9% RubberNe14 slub in the warp and with 74% cotton/26% rubber Ne10 Stretch yarnin accordance with the present invention. The invention in the weft yarnis with cotton fibrous sheath and core with two rubber threads. Both ofthe average draft is with 3.2. We can see the sample had weight 13oz/sq.yd. (after washed), good stretch (55.4%), good shrinkage (−9%) andgrowth (5%).

The present invention may be embodied in other specific forms withoutdeparting from the spirit or essential characteristics thereof. Thepresent embodiment is therefore to be considered in all respects asillustrative and not restrictive. The scope of the invention isindicated by the appended claims rather than by the foregoingdescription, and all changes that come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed is:
 1. A ring spun stretch yarn comprising at least twoelastomeric filaments with at least two different mean drafts, whereinthe mean draft on individual filament is varied and two fibrous sheathof at least one staple fiber, and wherein the elastomeric filaments havea denier from 20 to 140 and said the fibrous sheath has an Englishcotton yarn count Ne from 4 to
 60. 2. The stretch yarn of claim 1,wherein said fibrous sheath comprises natural or synthetic staplefibers, cotton, polyester, rayon, wool, nylon, acrylic or combinationthereof.
 3. The stretch yarn of claim 1, wherein the mean draft of theelastomeric filament is from 1.05 to
 5. 4. The stretch yarn of claim 1,wherein the mean draft is calculated by individual actual draft/timealong that elastomeric filament.
 5. The stretch yarn of claim 1, whereinthe draft/time of the elastomeric filament is controlled by electronicbut not limited.
 6. The stretch yarn of claim 1, wherein draft onindividual filament is varied in the range from ±50% of the mean draft,but not limited to this range.
 7. The stretch yarn of claim 1, whereinthe elastomeric filament is spandex/elastane/elastomer but not limited.8. The stretch yarn of claim 1, wherein the elastomeric filament can beat least one type material.
 9. The stretch yarn of claim 1, wherein thefibrous sheath can be natural fibers, regenerated fibers, syntheticfibers and a combination thereof.
 10. The stretch yarn of claim 1,wherein the stretch yarn can be used in producing slub yarn/normal yarnwhich can get some special fancy effect.
 11. A woven fabric comprisingthe stretch yarn of claim 1 in warp or filling or both.
 12. The wovenfabric of claim 11, wherein the fabric is denim or piece dyed.
 13. Aknitted fabric comprising the stretch yarn of claim
 1. 14. A sweatercomprising the stretch yarn of claim 1.